The present invention relates to a packaging system for combining and dispensing a product at its point of use. The packaging system herein described is particularly useful for combining and dispensing a mixture of products.
The packaging of products is a significant consideration for manufacturers and consumers. The factors requiring consideration in selecting a particular form of packaging include the suitability of the packaging for containing the product throughout its shelf life and the ease with which the product can be dispensed.
Many household products are packaged in pressurized aerosol containers. There are three main types of aerosol containers: standard, piston and bag-in-can. Standard aerosol containers are formed from aluminum or tin plate and contain a mixture of product and pressurized propellant. A piston can is an aluminum can having the product separated from the pressurized propellant by a piston which is normally polypropylene. A bag-in-can container is formed from aluminum or tin.
Other parts of the complete aerosol device, such as the valve used and the actuator, are also selected upon their suitability having regard to the nature of the product and the type of aerosol container. The method of filling the container will also be affected similarly.
Up to now aerosol devices could only be used with products that are stable within the container and therefore have a suitable shelf-life. However, there are many materials which must be produced from two or more ingredients mixed just prior to use. Examples of such products include: glue and hardener, glass fibre resin and catalyst, epoxy paints, hair colorants and cement/concrete.
The present invention provides a packaging system having a first container containing a first ingredient and a second container containing a second ingredient, the first and second containers being adapted for connection together such that upon deployment of the packaging system the first ingredient is displaced from said first container into said second container and an admixture of said first and second ingredients is subsequently dispensed from the packaging system.
More particularly, the packaging system according to the invention comprises:
a) a first container having a valve-controlling the opening of an outlet and containing a first ingredient;
b) a second container having a openable entry portion, containing a second ingredient; and
c) means for connecting the first and second containers together in order to allow the first ingredient to be displaced from the first container into the second container via the entry portion thereof, so that the first and second ingredients are admixed in the second container to form a final product.
Conveniently the passage of the first ingredient from the first container through to the second container causes the first ingredient to be intimately blended with the second ingredient.
It is preferred that the connecting means comprises a conduit to transfer said first ingredient into said second ingredient.
Preferably the containers are each pressurized aerosol containers, and the initial pressure in the second container may be less than that in the first container.
In one embodiment the first container is a piston-style aerosol container. The first ingredient is placed into the first container which is then fitted with a top valve. The first container may then be sterilized, for example by autoclave. The container is then pressurized by inserting a propellant below the piston via an aperture in the bottom of the can. A preferred propellant is nitrogen gas, but a wide variety of propellants can be used since there is no contact between the propellant and the first ingredient (these being separated by the piston). The pressurized container is then sealed with a rubber bung or other suitable means. Alternatively the first container may be a bag-in-can style aerosol container, the first ingredient being separated form the propellant by the bag.
In one embodiment the second container may be an aerosol container of known type, advantageously adapted by having as an openable entry portion a Nicholson valve or bung or other seal preferably located in the bottom thereof. An example of another seal or entry portion would be a thin portion or membrane which could be pierced open. Thus, the second container is filled with an appropriate quantity of second ingredient via the top of the can which is then closed using a standard valve. The container may be pressurized by inserting a suitable propellant (desirably an inert propellant that does not react with the first and second ingredients). Alternatively, the second container may become sufficiently pressurized by the transfer of the first ingredient.
Optionally the connecting means are also provided with means to hold the first and second containers in suitable juxtaposition.
The conduit may be a tube, preferably composed of plastics material.
In a preferred embodiment the first container is positioned beneath the second container and connected thereto via the connecting means. It is also preferred that the first container has a standard directionally biased pressure activated valve as commonly provided on an aerosol can.
Optionally the conduit cooperates with the openable entry portion of the second container so that when the entry is opened, the conduit permits entry of the first ingredient into the second container to take place.
Optionally the conduit is shaped to co-operate with the valve of the first container and preferably to open it. For example the conduit may comprise a bayonet-shaped end.
Preferably the second container has a bottom-mounted Nicholson valve or a bung which is removed or displaced into the second container by the connecting means to allow the entry of the first ingredient into the second container. Thus, in one embodiment the conduit may cooperate with the Nicholson valve located in the bottom surface of the second container and will displace the valve inwardly upon connection.
In one preferred embodiment the connecting means is shaped and sized to facilitate the admixture of the first and second ingredients within the second container. To aid suitable dispension of the first ingredient, the conduit may terminate in a blind ending and possess multiple openings (usually 2, 3 or 4) in the side of the conduit, generally adjacent the blind end thereof. In one example the conduit openings may be shaped and dimensioned to dispense the first ingredient in a spiral flow so as to promote good admixture of the first and second ingredients.
In one embodiment the connecting means comprises a first sleeve projecting downwardly which engages the top of the first container and a second sleeve projecting upwardly which engages the bottom of the second container. Thus, the first container is positioned correctly with respect to the second container via the connecting means. This sleeve, may be composed of plastics material. The conduit is carried within the aperture of the sleeve. Desirably the sleeve forms a close-fit with the first and second containers. For example, the internal surface of the sleeve may comprise a series of ridges extending circumferentially. In use the first container may be pushed past one or more of these ridges to be locked into place and cause transfer of the first ingredient to the second container via the conduit.
Advantageously, means to actuate the displacement of the first ingredient to the second container includes means to hold the first and second containers in suitable juxtaposition.
The sleeve may be used to retain the first container beneath the second container during both storage and distribution. The sleeve will also be responsible for holding the containers together such that the contents of the first container may be transferred into the second container.
Optionally the sleeve may include or be attached to an anti-tamper device.
The connecting means may be moulded from plastics material as a one piece unit. Alternatively, and desirably, the sleeve may be formed from a first and second part which are rotatable relative to each other. The first part comprises both the conduit and the first and second sleeves. The second part comprises a third sleeve which is secured to or part of the bottom of the second container. The second and third sleeves have corresponding screw threads, which allow these second and third sleeves to be moved from a first position where the conduit is not actuating the openable entry portion to a second position where said conduit actuates said openable entry when transfer of the first ingredient is required.
Thus, the sleeve parts may simply be screwed together to initiate transfer of the first ingredient. Desirably there may be a ratchet mechanism to prevent reversal of the rotation of the sleeve parts. In one embodiment the relative rotation of the sleeve parts is through approximately 120xc2x0.
Preferably each of the containers may be sterilized, for example by autoclave techniques or by irradiation.
Conveniently the second container may be filled with the second ingredient via an aperture in the bottom of the container which is then sealed, for example with a rubber bung or Nicholson valve. This seal or valve may then be pushed into the container by the connecting means upon activation.
Preferably also the second container has a top mounted actuator which controls the dispension of its contents.
Optionally each of the containers may also be adapted to dispense the ingredients contained therein in a conventional manner.
In a preferred embodiment the first ingredient is a gel, preferably a foamable gel, and the second ingredient is a powder.
In a preferred embodiment of the invention the packaging system of the present invention is designed to discharge the material described in WO-A-96/17595 of Giltech Limited wherein the powder constituent of said formulation is the second ingredient and is contained within the second container and the gel constituent of said formulation is the first ingredient and is contained within the first container.
In a preferred embodiment of the invention the connecting means is used to connect two aerosol canisters, which together contain the ingredients required to make a silver ion releasing water-soluble glass held in an alginate foam as described in WO-A-96/17595 of Giltech Limited.
In this embodiment the first container is a piston type aerosol canister, which contains a foamable gel (eg alginate) which is pressurized to approximately 130 psi, for example with nitrogen gas. The second container contains the powder ingredients of said foam (eg a water-soluble glass powder) and is pressurized to approximately 50 psi, for example with a liquified petroleum gas (eg CFC, HC, HFC propellants). However, the first container may also be a bag-in-can aerosol container where the first ingredient is separated from the propellant by a bag.
The whole apparatus may be shaken after transfer of a the first ingredient to ensure proper mixing of the first and second ingredients before the foam can be discharged. Once discharge is complete the apparatus may be discarded.
The packaging system described herein is based upon pressure differentials. When the containers are connected, if the pressure in the second container is less than that in the first container, upon connection the contents of the first container will flow into the second container as required. At equilibrium if the pressure in the second container is equal to the pressure in the first container no further transfer of material will take place. If the pressure in the second container is greater than the pressure in the first container the contents of the second container could flow back into the first container. This flow can however be prevented by the use of a one way valve at the top of the first container.
The propellant selected for the second container is usually an excipient of the final product, which is produced by mixing the contents of the first container with the second container. The excipient is a substance conveniently used as a medium or a vehicle for administering the final product. It is advantageously a gas which does not react with the first and second ingredients. However, if a barrier type canister is used as the first container, the propellant used for the first container will not be introduced into the second container. It will not therefore affect the final product.
If a liquified gas is used as the propellant in the second container, the vapour pressure of this gas can be determined by mixing quantities of liquified gases at various vapour pressures until the desired pressure is reached. Vapour pressure is that pressure at which the closed system is at equilibrium.
This can be explained in more detail as follows: If a known volume of liquid gas is introduced into a vacuum at a given temperature T the liquified gas will boil and vaporize to occupy all of the available space in the container. The pressure in the container will rise as the gas expands. At equilibrium the remaining liquified gas will not have enough energy to vaporize and the pressure of the gaseous phase is not high enough to cause condensation of the gas. This equilibrium point can be measured as a stable pressure reading at the valve or entry point. A reduction in the volume of the container will lead to an increase in the volume of liquified gas and vice versa, but the pressure will remain constant at a given temperature.
The liquified gas propellants give a constant pressure throughout the expulsion of products. They can also readily dispense thicker product more easily than compressed gas as their pressure will not decrease until all the liquid phase propellant has been expelled.
If a pressurized gas (air, nitrogen, etc) was used in the second container then the pressure fill would have to be lower than the first container to allow for a pressure increase when product is introduced from the first container. If the pressure equalizes during the transfer flow of product will cease. As the product is dispensed the pressure in the second container will decrease and dispersion will be slowed.
If the first container and the second container are standard aerosol canisters with no barrier type system, product and propellant from the first container will flow into the second container until equilibrium is reached in the two containers.
The principles of the present invention could be used to mix contents from virtually any number of containers (so long as there is an appropriate pressure difference between one container and the next).
The connection means of the present invention thus provides a means for mixing the contents of two or more separate aerosol containers together in one of the aforementioned aerosol containers. This is particularly useful when an aerosol dispenser is required to dispense a mixture of ingredients that would otherwise be too unstable to be stored in just one single aerosol container.
The packaging system of the invention may comprise more than two containers which are successively connected together with connection means. Advantageously, each container would be appropriately pressurized to drive its contents into the next container following activation of the connecting means linking the two containers together, to form an admixture. Thus, the contents of the initial container will be transferred to its immediate neighbour and the admixture so formed will be subsequently transferred to the next container of the series. This process will be repeated until the final container contains the full admixture which can then be dispensed.